Double die for making l-punchings



W. E. LAIRD.

DOUBLE DIE FOR MAKING L-PUNCHINGS. APPLICATION FILED DCT. 28. 1918.

UNITED sTATEs PATENT oEEioE.

WESLEY E. LAIRD, 0F PITTSFIELD, MASSACHUSETTS,`ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK. v

DOUBLE DIE FOR MAKING L-PUNCHINGS.

Specification of Letters Patent. Patented Mal'. 16, 1920.

Application led October 28, 1918. Serial No. 259,891.

To all whom it 4may concern.'

Be it known that I, WESLEY E. LAIRD, a citizen of the United States,residing at Pittsfield, in the county of Berkshire, State ofMassachusetts, have invented certain new and useful Improvements inDouble Dies for Making L-Punchings, of which the following is a4spec-ication.

Hy invention relates to dies, and has for its object an arrangement ofparts capable of producing an L-punching of a given size from a givenpiece of stock with the least possible waste of material.

More especially my invention relates to a die-having for its specificobject the provision of an arrangement of parts for carrying into effectthe method of producing L-shaped punchings, with the least possiblewaste of material disclosed in the application for Letters Patent,Serial No. 259,881, led by J. J. Frank, on October 26, 1918.

In the application above referred to it has been proposed to use a pieceof metal stock of nearly twice the width normally required for makingplain L-punchings, and as it passes through the machine, to punch twosuch Ls from the stock across the sheet having the squared ends ofhomologous legs of the Ls abutting where the shapes are notcomplementary, thereby avoiding the necessarily attendant waste inmaking Ls having the ends of its legs of desired shapes, along oneentire edge of the stock.

In order to accomplish this saving without additional offsettingexpenditures in the course of manufacture, it is not only desired thatthe two Ls, one from each side of the stock, should be made with onlyone handling of the material, and that the punch and die parts should beas simple and rugged as possible; it being especially desirable to avoidthe use of a compound die by reason of its increased cost of manufactureand upkeep.

To this end the die of my invention is designed to have two separateL-shaped punches for shearing off the two L-shaped punchingsindependently, one punch being in advance of the other. This arrangementof punches and dies results in a shearing edge having a somewhatirregular contour but the resulting die has all the advantages of asimple die in the course of manufacture and upkeep.

For a more complete understanding of the nature and objects of myinvention reference should be had to the following detailed descriptionwhen taken in connection with the accompanying drawings in which Figure1 shows a plan view of a coperating punch and die embodying myinvention. is a sectional view of the die plate taken on line'2-2 inFig. 1. `Fig. 3 is an explanatory diagram, and Fig. 4 is a fragmentarysection taken on line 4-4 in Fig. 1.

Referring now to the drawing, 10 denotes a stationary member, or dieplate, having therein two L-shaped cavities at A and B respectively,bounded by die steels or members 11, 12, 13, 14, etc., to 22, securedabout those portions of the periphery of the two cavities, as shown inFig. 2, which const-itutes the shearing edges, the other portions beingbounded by metal guides, shown at 23, 24, and 25, having the upstandingledges 23', 24 and 25 respectively, serving not only to prevent rapidwear of the metal in member 10 by the punches, but also as stops for thestock being fed.

The member 27 carries the L-shaped punches a and b (shown in section inFig. 1) which coperate with the edges of the die steels 11, 12, 13,etc., to shear oil the punchings from the stock as it is advanced underthe punches at each successive stroke of the ram. The member 27 is alsoprovided with recesses, shown at r in'Fig. 4, for accommodating theledges onguides 23, 24 and :25 on the down stroke.

The cavities A and B in the member 10 are preferably made slightly widerthan the punches a and b so as to provide a slight clearance spacebetween the punches and that portion of the walls of the cavities notbounded by die steels. The guiding ledges 23", 24 and 25', however, fitsnugly against the punches a and b, and in order to prevent theirdisplacement from this position, the under side of the base portion ofeach of these guides is provided with a depending lip 28, as shown inFig. 4, arranged to extend slightly Vinto one of the cavities. Thisarrangement has the advantage that Fig. 2 A

the punchings shorn oft' by the dies may readily leave the punches,passing down through the cavities A and B by reason of the clearancespace thus provided, but at the same time are prevented from springingof the strip 2.

back into the path of the punches, on account of any inherent resiliencein the punchings, by means of the lips 28.

In addition to the cavities A and B, the member l0 is preferablyprovided with several minor cavities, such as shown at 30, 31, 32, etc.,to 36, which servechiely as clearance spaces for securing the exactadjustment of the die steels which are held in place by means ofsuitable dowels or screws, such as shown at C. To insure that the stockbeing fed to the dies shall at all times be advanced under the dies inthe right angular direction, I have provided the guide 37 having thelaterally extending base iange 38 on which the edge of the stock whichprojects beyond member 10 is designed to slide. This guide is secured tothe member 10 by any suitable means such as the boltsl shown at 39.

As before remarked, the punches and dies, in accordance with myinvention, are arranged one in advance of the other; consequently I haveshown the punch a as advanced beyond the punch so as to take an L-shapedpunching out of what is here shown as the upper side of the stock, onestroke of the ram before the abutting L-shaped punching is taken out bythe punch b. Obviously, however, the punch t need not be arranged to beonly one stroke in advance of punch Z), but may be arranged any numberof strokes in advance as conditions may indicate, which will be readilyunderstood by reference to Fig. 3.

In Fig. 3, S denotes a piece of stock whose width is nearly twice thatfrom which single Ls wouldy be normally struck. Suppose the upper edgeof this piece of stock is traveling in the guide 37, then for thearrangement shown when the punch is up, the stock would be advanceduntil the straight edge of its end caught against the nose 40 of the die17. The downward stroke oil the ram would cause punch a to take out thetriangle 1 and punch b to take off the triangle 1. The stock S is thenadvanced upon the upstroke of the ram so that the V-shaped edge of thestock, formed by the removal of triangles 1 and 1, abuts against guides23, 24 and 25. The downward movement of the ram now causes punch a totake out the fragmentary L `denoted 2, while punch b takes The thirdadvance of the stock permits the third downward stroke of the punches t0take out the imperfect Ls marked 3 and 3, respectively.

The sheared edge of the stock denoted by the lines 6,7, g, lz, and z' isnow the standard contour which the stock will retain as it is y advancedunder the punches to produce complete L-punchings, for on the fourthadvance the punches will shear olf the complete Ls marked 4 and 4respectively.

The subsequent advances of the stock re-' sult in the shearing 0H of Ls5 and 5, then 6 and 6, etc. During the advance of the stock S the guides23, 24 and 25, (particularly that at 21) will act to draw the stocklaterally into coincidence with the contour of the cutting dies shouldthere be any displacement of the stock in a sidewise direction, asoccasionally occurs while punching due t0 the warping of stock from thestrains occasioned by shearing.

From Fig. 3 it is clearly seen that the L whose homologous leg abuts theshort leg of the L marked 4, is the L marked 3, which was taken out bythe punch a one stroke before the punch b sheared off the L marked l.This advanced taking out of the L.

marked 3 by punch L forms the edges marked g, It and 71 so that it isunnecessary to provide the die member 17 with a cutting edge. In casethe punch a is advanced more than one stroke ahead of punch Z9, thecontour of the stock between lines f and IL would be a zig-zag line,following these portions marked c g and 7c. However, the edge of the diemember 17, which coperates with punch b, is provided with a cutting edgeto shear off any metal that might otherwise remain due to anirregularity in the feed of the stock and thereby produce an L havingone leg too long.

-nose 40 is formed to cut out the; triangles marked t in Fig. 3, as thestock is advanced under punch a, and thus forming an L which wouldotherwise have a large interior llet.

The die member 16 gives the desired'interior contour to the L s stampedfrom the lower side of the stock so that it is necessary to provide thedie member 23 to shear olf triangles u from the knee of the Ls abo-ut tobe sheared off by punch b.

Having now described what is at present the best means known to me forcarrying out an embodiment of my invention, I would have it understoodthat such means are merely illustrative and that I do not mean to belimited thereby to the exact details shown nor in the choice ofrecognized equivalents except as defined in my claims hereunto appended.

What I claim as new and desire to secure by Letters lPatent of theUnited States, is

1. The combination of two sets of relatively movable dies and punches,each set having cooperating uncomplementary L- shaped configurations offixed dimensions, one set being located with respect to the other so asto take its punching out of the stock fed thereto simultaneously, apredetermined number of strokes in advance of said other set.

2. The combination of two sets of relatively movable dies and punches,each set having coperating uncomplementary L- shaped configurations offixed dimensions, and a guide for the stock fed thereto, one of saidsets being so located along the line of feed that it takes its punchingout of the stock simultaneously a predetermined number of strokes inadvance of the other set.

3. The combination' of two sets of relatively movable dies and punches,each set having cooperating uncomplementary L- shaped configurations offixed dimensions, the sets being so arranged that homologous legs of theLs extend in opposite directions, but displaced along the line of feed adistance equal to the advance for a punching.

l. The combination of two sets of relatively movable dies and puncheseach set having cooperating L-shaped configurations of fixed dimensionsfor taking uncomplementar f L-shaped punching out of a sheet of stock ofsubstantially double width across the line of feed, the homologous legsof the Ls extending in opposite directions but displaced from each otheralong the line of feed a-distance equal to the advance for a punching.

5. tively movable dies and punches, each set having cooperating plainL-shaped configurations of the same fixed dimensions, and a guide forthe stock fed thereto, the short legs of the Ls being arranged to extendtoward each other and the long legs to extend away The combination oftwo sets of relafrom each other, the short leg of one set beingdisplaced relatively to the other along the line of feed a distanceequal to the advance for a punching.

6. The combination of two sets of relatively movable dies and punches,each set having cooperating plain L-shaped congurations of fixeddimensions, and stops for the stock being fed arranged adjacent to saiddies so as to draw the shorn edge of the stock into coincidence with thecontour 0f said dies, one of said sets being located a predeterminednumber of strokes in advance of the other set.

7. The combination of two sets of relatively movable dies and punches,each set having cooperating plain L-shaped configurations of fixeddimensions, a guide for the stock being fed, and stops for the stockarranged adJacent to said dies so as to draw the shorn edge of the stockinto coincidence with the contour of said dies, one of said setsv beingso located along the line of feed that it simultaneously takes itspunchingout of the stock one stroke in advance of the other set. Y

8. The combination of two sets of relatively movable dies and punches,each set having cooperating L-shaped configurations of fixed dimensions,and stops for the stock being fed arranged adjacent to said dies eachbeing provided with a depending lip extending slightly into the cavitybounded by said dies thereby providing a clearance space for thepunchings in said cavity slightly below the shearing edges.

In witness whereof I) have hereunto set my hand this 24th day ofOctober, 1918.

WESLEY E. LAIRD.

